Combination triathlon aero handlebar and stem assemblies (referred to herein as “handlebar assemblies”) are known and typically comprise a unitary main body, often advantageously fabricated from a carbon fiber composite, and including a stem portion, right and left aerofoil portions extending outwardly of the stem and left and right handle portions situated at the ends of the respective aerofoil portions. A pair of relatively closely spaced tubular extensions extends forwardly from the body on either side of the stem portion. The extensions are mounted to the body by way of an extension mount assembly that includes a circular clamp to secure the extensions in place. The extension mount assembly also typically includes elongated fasteners and vertical extension spacers through which the entire assembly is secured to the body with the circular clamp located a desired distance above the body. On top of the extension mount assembly, an elbow rest platform is provided that is typically secured to the extension mount assembly through fasteners. Resilient cushioned pads may be provided to rest on the top of the elbow platform.
The stem portion mounts to a portion of an associated bicycle's fork steerer tube that extends upwardly from the frame of the bike to which it is rotatably secured. Stem height spacers are used between a bicycle head tube and the bottom of the stem portion to set the height of the rest of the handlebar assembly. To change the relative height of the handlebar assembly, the rider must remove the assembly from the steerer tube and add or subtract spacers.
In at least some assemblies the height of the tubular inner extensions and the associated elbow rest platforms above the stem, associated aerofoil portions and left and right handle portions can be adjusted through the use of spacers as well, such as is described in U.S. Pat. No. 9,415,825 entitled Combination Bicycle Handlebar and Stem Assembly, which utilizes a left and right spacer columns to adjust elbow rest platform height. U.S. Pat. No. 9,415,825 is incorporated herein in its entirety. While a significant improvement over assemblies herein the height is not adjustable, changing the height can be time consuming and due to the use of spacers of finite height, the height of the stack is not from a practical standpoint infinitely adjustable.